1. Field of the Invention
This invention relates to an apparatus for measuring and displaying an amount of a noxious waste gas exhausted from a vehicle in real time, and controlling an amount of fuel to be fed into an engine based on the measurement result.
2. Description of the Related Art
According to the waste gas regulation, an automobile should take a waste gas test at regular intervals and when it acquires a formal approval after manufactured. In a test room, an automobile should be driven under a specified condition in a test room in order to measure accurately noxious substances contained in a waste gas that would be exhausted while the automobile is being driven on a road.
And, various complicated devices are connected with a test equipment. For example, a chassis dynamometer simulates the air resistance, the road slope, the driving resistance, and so on, to apply various practical driving conditions of many roads to a car being tested. While a car is being driven with a chassis dynamometer, an engine is cooled by a cooling fan positioned at the front of a car, and a waste gas exhausted during the test driving is caught. After the test driving done, the caught waste gas is analyzed to measure noxious substances contained in a waste gas.
A test method and regulated volume about a waste gas are mostly different between all countries. The level of testing technology is also differentiated as well. However, a testing procedure for measuring an amount of noxious gases has been agreed internationally. The CVSD (Constant Volume Sampling Dilution) method has been adopted and generalized as a standard testing procedure since 1982, however, the CVSD method is conducted a little differently according to each country.
FIG. 1 shows a schematic process diagram for conducting the CVSD method. In the CVSD method, if a car exhausts a waste gas while being driven according to a test driving cycle sequence, the waste gas is diluted through being mingled with the air after filtered, and then is inhaled by a special pump. The diluting air volume is adjusted in the total volume flow of an exhaust gas and diluting air to maintain the ratio of the diluting air to total volume flow to be constant.
However, in the CVSD method, a measuring apparatus should be highly precise enough to detect minute change of the dilution ratio since the concentration of each noxious gas becomes low according to the dilution ratio. Moreover, the CVSD method can not be applied to a car being driven on the real road.
The conventional waste gas measuring method including the aforementioned CVSD method is on the basis of chemical analysis. This chemical-based measuring method is very sensitive to ambient temperature, humidity, and so on, so that a chemical-based measuring apparatus developed to be insensitive to the atmospheric factors is very expensive and its operating method is also very complicated. Therefore, the conventional measuring apparatus adopting chemical analyzing method can not be distributed over every measuring post on the road, and it is not applicable to measure noxious gases exhausted from a moving car in real time either.
It is an object of the present invention to provide a ceramic gas sensor being able to sense a noxious waste gas electrically in real time.
It is another object of the present invention to provide an apparatus for displaying an amount of a noxious waste gas being exhausted and controlling an amount of fuel to feed an engine with based on a measured data for a noxious waste gas.
A waste gas sensor according to the present invention comprises a porous ceramic in which pores are formed; an insulating supporter supporting the porous ceramic at the bottom of the porous ceramic; an insulating filler covering the porous ceramic; a pair of electrodes inserted vertically into the porous ceramic through the insulating filler and separating them into three parts; a pair of thermal compensating plates, which are inserted vertically into the insulating filler to support the pair of electrodes, transforming an electrical energy into a thermal energy; lead wires connected to each of the electrodes and the thermal compensating plates; and an insulating lid covering the top of the filler and separating the lead wires each other, wherein the lead wires penetrate the lid.
A fuel controlling apparatus according to the present invention comprises the waste gas sensor, which is installed in an exhaust pipe, generating a leakage current proportional to an amount of conductive particles contained in a waste gas and maintaining its temperature constantly by transforming an electrical energy into a thermal energy; a measuring unit computing an amount of gas composition based on the generated leakage current; a controlling unit adjusting an amount of fuel to be fed into an engine from a fuel tank based on the computed value for the amount of gas composition; and a displaying unit displaying the computed values numerically or turning on a LED to alarm under the control of the controlling unit.